Astronomers have discovered the closest candidate black holes stellar mass, which is a triple system of stars visible to the naked eye in the southern hemisphere of the Earth. The lower limit on the mass of this black hole is estimated at $ 4.2 solar masses and the distance to the system is one thousand light-years. Article published in the journal Astronomy&Astrophysics, briefly about work it is told on the website of the European southern Observatory.
The existence of black holes as regions of space-time, which is due to the strong gravitation can not leave even a photon was predicted over a hundred years ago in the framework of General relativity. For a long time astronomers had only indirect evidence of their existence, such as a strong gravitational influence on other bodies, the detection of relativistic jets in distant galaxies or observation for a bright accretion disks in binary systems. Only recently, with the development of methods of observations and processing of data, scientists were able to obtain direct evidence of the reality of such bodies in the Universe in the form of the shadow a black hole in the center of the active galaxy M87, and has recorded gravitational waves from mergers of black holes and confirmed for the first time predicted by the theory of relativity features of the motion of stars in a strong gravitational field near the supermassive black hole at the center of the milky Way.
Until recently, the closest to the Earth known black hole was considered to be one of the components of x-ray binaries A0620-00, located at a distance of three thousand light years away in the constellation of the Unicorn. Now a team of astronomers led by Thomas Rivinius (Thomas Rivinius) of the European southern Observatory reported the discovery of an even closer black hole in the triple star system of HR 6819, which is distant from the Sun a thousand light years. The system visible to the naked eye in the southern constellation of the Telescope in a clear moonless night.
The discovery was made in the course of the study system with spectrograph FEROS (Fibre Extended Range Optical Spectrograph) mounted at the 2.2 m MPG telescope at the Observatory of La Silla in Chile. HR 6819 consists of Ve stars, which is in a wide orbit around a close pair of stars of type B3 III and invisible companion in a circular orbit. The orbital period of a close binary is 40 earth days. Palampiddi radial velocity in the interior of the star is equal 61,3 kilometers per second, together with the estimation of its minimum mass 6.3 mass of the Sun gives the lower limit of the mass of invisible bodies 4.2 the mass of the Sun. This means that we face a black hole of stellar mass, which does not absorb in the moment stuff.
Scientists believe that this discovery will provide an impetus to search for other “quiet” black holes. If we consider that about twenty percent of all the stars of earlier type are triple systems, and 0.01 percent of them have the structure of the system, similar to HR 6819, then the discrepancy between the expected and observed number of black holes in the galaxy may be reduced by several orders of magnitude, if these black holes are found in such systems. In addition, in systems with a configuration that is similar to the HR 6819, may occur of the merger of two black holes, which will cause a burst of gravitational waves that can be registered.
To see the “shadow” of a black hole and look into the bowels of quasars, astronomers were helped by the method of radiointerferometry with an extra-long wheelbase, one of the founders of which is an astrophysicist Nikolai Semenovich Kardashev, the discoveries which you can find from our material, “Creator “Radioastron””.